Vertex-Standard is now owned by Motorola.
They build decent radios, but their dealer support in Metro Atlanta isn't there, or at least compared to Kenwood and Icom (the other two Jap radio companies). Kenwood is now the world's second largest manufacturer of two-way radios, second only to Ma M.
I don't think the VX-180 is a fireground radio. Too small, too easy to lose, and the knobs seem difficult to operate if you're in turnout gear with gloves on. Not sure how they would hold up in the heat of a fire. All small radios (physically speaking) don't perform as well as larger full sized radios. This is due to the lack of counterpoise for the antenna system, which is more critical on lower bands (especially VHF).
The VX-600/900 is more suited for firefighting. But then it's considerably more expensive than the VX-180.
The HT1000 is no longer in production. It's a solid radio, the later revisions had lots of bug fixes (model numbers end in CN or DN) and the later could do narrowband splinter channels. Lots of accessories for them on the market and they're cheap. You can find HT1000's for around a C-note, just make sure to get a CN or DN revision (ask for the model number, e.g. H01KDC9AA3DN).
For not much more, the MT2000 is a step up, built on the same platform as the HT1K just adds a display (and 10 times the channel capacity, 160 versus 16 for the HT1K.)
Other worthwhile consideration are the Kenwood TK-2180, while on the higher end, it's a current production radio and a workhorse at that, lots of channel capacity, all kinds of signaling built-in, narrowband support (6.25KHz too), and rugged construction.
If you're on a budget, grab a used HT1000 (CN/DN). Otherwise get a Kenwood.